Iron plough coulter

Roman Britain, 1st-4th century AD
From Great Witcombe, Gloucestershire

The coulter was a technical innovation introduced to Britain by
the Romans. Its function was to make a vertical cut in advance of
the plough-share, which then undercut the furrow made by the
coulter. This made it easier to cultivate heavy soils. Roman
coulters were therefore stout knife-like iron blades with a heavy
shaft by which they were secured to the plough's wooden beam.

W.H. Manning, Catalogue of the Romano-Britis (London, The British Museum Press, 1985)